Many different fuel systems are utilized to introduce fuel into the combustion chambers of an engine. One type of fuel system is known as the common rail system. A typical common rail fuel system utilizes one or more pumping mechanisms to pressurize fuel and direct the pressurized fuel to a common manifold also known as the common rail. Individual injectors draw pressurized fuel from the common rail and inject one or more shots of fuel per cycle into the combustion chambers. In order to optimize engine operation, fuel within the rail is maintained within a desired pressure range through the precise control of the pumping mechanisms.
Situations may arise in which this precise control is interrupted, pressure fluctuations or spikes occur, or various portions of the fuel system fail. In these situations, there is a possibility that fuel pressures within the common rail could reach levels that have the potential to damage the components of the fuel system. One way to protect the common rail from such excessive pressures is to selectively drain fuel from the common rail as the pressure of the fuel within it exceeds a predetermined maximum threshold value. However, if too much fuel is drained, the pressure of the fuel within the common rail may drop below a certain minimum pressure at which the fuel injectors and engine will be able to continue operating in at least a limited operational mode, or “limp home” mode, and the engine may shut off. If the engine shuts off suddenly, the machine, truck, or other piece of equipment the engine is powering may be left in an undesirable state, position, or location. Moreover, depending on the problem or problems that lead to the excessive pressure within the fuel system, the rate at which the fuel will need to be drained from the common rail to maintain the minimum pressure may vary.
The disclosed pressure relief valve is directed to overcoming one or more of the problems set forth above or other problems.